A. Field of the Invention
This invention relates to a suction control unit for an endoscope, which can switch over from one passage to another in the endoscope.
B. Description of the Prior Art
A typical suction control unit for an endoscope is disclosed in Japanese Utility Model Publication No. 81-9941.
This suction control unit is fitted in the opening portion of an endoscope, through which a treating instrument can be inserted into a body cabity. In this suction control unit, a cylindrical main body is connected to a forceps channel through which forceps or the like is inserted, a suction port communicating with the suction unit is cut in the middle portion of the side wall of the main body, and a cylinder is fixed inside the main body. A sliding valve for opening and closing the suction port is provided in the cylinder. The valve is normally open, having the opening of the main body communicate with the suction unit, thus lightening the load on a suction pump of the suction unit. To draws the filth or the like from the abdominal cavity through the forceps channel, closes the opening of the main body with his finger.
In the suction control unit disclosed in Japanese Utility Model Disclosure (Kokai) No. 85-23001, a valve seat is formed on the bottom of a cylindrical main body, and an elastic valve member is provided in the main body.
However, the problem with the above suction control unit is that the operator has to close the opening (relief port) with his finger in a suction operation, and that filth substances drawn up from the abdominal cavity through the forceps channel flows to the relief port, thus smearing the operator's finger, which is unhygienic.